KR20090037993A - Cutting tool with adjustable indexable cutting insert - Google Patents

Abstract

A cutting tool (10) is provided and includes a plurality of cutting inserts (12, 100) located in respective insert pockets (14, 114). The cutting inserts (12, 100) each include a top cutting plane (60, 102) with at least one cutting edge (70, 72, 128, 130) and a bottom support plane (62, 104). The top cutting plane (60, 102) includes an engagement portion (64, 108) for mating with a respective engagement portion (66,110) located in the respective insert pocket (14, 114). A clamping wedge (18) clamps the cutting insert (12, 100) against the respective insert pocket (14, 114). A shear resistance created between the engagement portions (64,108) of the cutting insert (12, 100) and the respective insert pocket (14, 114) during operation of the tool (10) is greater than a centrifugal force created during operation of the cutting tool (10). In an exemplary embodiment, the engagement portions (64, 108) are shown as a plurality of serrations (67, 120). The cutting tool (10) is particularly useful in high speed milling operations.

Description

Cutting tools with adjustable removable cutting inserts {CUTTING TOOL WITH ADJUSTABLE INDEXABLE CUTTING INSERT}

The present invention relates to a cutting tool, and more particularly to a high speed milling cutter.

Cutting tools for machining work pieces of metal, such as steel, aluminum, titanium, and the like, typically include a tool holder for mounting a removable cutting insert. During operation of the cutting tool, centrifugal force F _z is generated. In high speed milling operations, the centrifugal force (F _z ) becomes important due to the relationship with the spindle speed (which is proportional to twice the spindle speed in power) according to the formula F _z = M * W ² * R, where M is the insert Is the distance between the center of rotation of the tool and the center of the insert of the mass. The cutting tool system loses equilibrium when the centrifugal force F _z exceeds the clamping force.

Referring to Fig. 20, the relationship of cutting speed to cutting force is shown. As shown in FIG. 20, an increase in cutting speed typically supports a decrease in cutting force. In particular, the hardness and strength of the product material during the manufacturing process is reduced due to the increased temperature of the cutting zone at high speeds. At the same time, the centrifugal force Fz applied to the insert increases rapidly (square to RPM). There is a point where the centrifugal force is greater than the magnitude of the cutting force. For high speed machining, centrifugal forces are typically greater than cutting forces. High speed machining typically has an RPM of over 10,000. However, the most traditional designs of inserts and clamping mechanisms are designed for low centrifugal forces and fail during high speed machining.

At high cutting speeds, the centrifugal force applied to the cutting element significantly exceeds the cutting force. If the clamping system fails, the kinetic energy accumulated during rotation is released according to E _K = (1/2) MV ² , where M is the mass of the object and V is the linear velocity at the moment of failure. . Due to the above relationship, one of the most important factors and requirements at high speed is the safety of the rotating tool.

The cutting tool is designed with an open pocket for the position of the cutting insert. The drawback with this particular design is that a high centrifugal force is applied to the tightening screw already stressed during clamping. When the screw fails, the insert is "free to fly" to release significant kinetic energy.

Known milling cutters using inserts with serrations on the surface or bottom face opposite to the cutting face of the insert, as shown, for example, in US Pat. No. 5,924,826, US Pat. No. 5,810,518 and US Pat. No. 6,921,234. There is a design. A drawback of these systems is the vulnerability of breakage of the crashing cutter body and insert. Since serrations are provided on the insert bottom and stretch to the maximum to support the insert load, the damage caused is generally very serious and very difficult to repair. Another drawback of these designs is the absence of an axial adjustment mechanism that allows precise positioning of the inserts without expensive grinding on the assembly.

Finally, as mentioned above, a single screw is used to fasten the insert in the open pocket. If the screw fails, the entire insert is released from the pocket. There is no additional shape or redundancy that further prevents the insert from loosening while the action breaks the screw. Therefore, there is a need for a technique for cutting tools in which the tightening screws are not affected by the cutting load and do not take significant centrifugal loads. Moreover, there is a need for techniques for redundant securing shapes in high speed applications.

Although the serration provided on the bottom surface absorbs an important part of the centrifugal force, it cannot absorb 100% of the centrifugal force. Due to the angular nature of the cross section of the serration, there is still a part of the centrifugal force with a "lifting" power. As the cutter rotation speed increases, the portion of the centrifugal force reflected through the serrations for the tightening screw also becomes large. At some point, the centrifugal force causes the insert to rise causing the cutting tool to fail. Another drawback of this type of cutting tool is that if the insert uses two cutting edges, the second edge experiences premature wear due to chips heating generated during cutting. In addition, the chip in progress will come into contact with elements of any adjustment mechanism, causing premature wear.

For cutting tools with carbide tips, the ability to stay on the insert becomes even more important. Since carbides are about twice as dense as steel, they are subjected to greater centrifugal loads. Due to its weight, it will fly further out of the pocket. Moreover, the carbide tips take most of the cutting load and are separated from the body. For applications using carbide tips, it is important that failures occur that cause a smaller likelihood of damage, which is emitted only in a small portion of the carbide tip.

Therefore, a need exists for an improved milling cutter for high speed milling operations. Moreover, there is a need for technology for inserts that are more resistant to wear and failure. Finally, there is a need for techniques for extra safe geometries in high speed applications, especially applications using heavier materials such as carbides.

According to a first aspect, the cutting tool comprises a tool body comprising at least one insert pocket. At least one cutting insert is held in at least one insert pocket. At least one cutting insert comprises an upper cutting surface and a lower supporting surface having at least one cutting edge. The upper cutting surface includes an engagement portion for mating with each engagement portion located in the at least one insert pocket. The tightening wedges tighten at least one cutting insert against at least one insert pocket. The shear resistance generated between the engagement of the at least one cutting insert and the at least one insert pocket during the operation of the tool is greater than the centrifugal force generated during the operation of the cutting tool.

According to a second aspect, the cutting insert comprises an upper cutting surface and a lower supporting surface having at least one cutting edge. The upper cutting surface includes an engagement portion for mating with each engagement portion of the cutting tool, the engagement portion providing a cross sectional shear area having a greater strength than the centrifugal force generated during operation of the cutting tool.

According to a third aspect, a method of assembling a cutting tool includes providing a cutting tool comprising a tool body with at least one insert pocket. At least one cutting insert is inserted into at least one insert pocket. The tightening screw is driven within the at least one insert pocket and tightened against the at least one cutting insert such that about 75% of the at least one insert is contained within the at least one insert pocket. The tightening wedge is adjusted to engage or remove at least one cutting insert.

1 is a perspective view of an embodiment of a cutting tool of the invention,

2 is a plan view of an embodiment of a cutting tool of the invention,

3 is a partial plan view of an embodiment of a cutting insert and a tightening wedge of a cutting tool of the present invention;

4 is a cross-sectional view of the embodiment of the cutting tool of the present invention shown in FIG. 2 taken along line A-A;

5 is a partially exposed perspective view of an embodiment of a cutting tool of the invention,

6 is a bottom perspective view of an embodiment of a tightening wedge of a cutting tool of the present invention,

7 is a top perspective view of an embodiment of a tightening wedge of a cutting tool of the present invention,

8A is a perspective view of an embodiment of a cutting insert of a cutting tool of the present invention,

8B is a bottom view of an embodiment of a cutting insert of a cutting tool of the present invention;

9A is a perspective view of another embodiment of a cutting insert of a cutting tool of the present invention;

9B is a bottom view of another embodiment of a cutting insert of a cutting tool of the present invention;

10A is a perspective view of another embodiment of a cutting insert of a cutting tool of the present invention,

10B is a bottom view of another embodiment of a cutting insert of a cutting tool of the present invention;

11A is a perspective view of another embodiment of a cutting insert of a cutting tool of the present invention,

11B is a bottom view of another embodiment of a cutting insert of a cutting tool of the present invention;

12A is a perspective view of another embodiment of a wiper cutting insert of a cutting tool of the present invention;

12B is a bottom view of another embodiment of a wiper cutting insert of a cutting tool of the present invention;

13A is a perspective view of an embodiment of a cutting insert comprising five serrations,

13B is a side view of an embodiment of a cutting insert comprising five serrations;

14A is a perspective view of another embodiment of a cutting insert comprising protective ribs,

14B is a side view of another embodiment of a cutting insert including a protective lip;

15A is a top view of another embodiment of a cutting insert including a protective lip;

15B is a top view of another embodiment of a cutting insert including a protective lip;

16 is a partial cross-sectional view of the tightening wedge and cutting insert according to another embodiment shown in FIGS. 14A and 14B;

17 is a partial cross-sectional view of the mating face and cutting insert of an insert pocket according to another embodiment shown in FIGS. 14A and 14B;

18 is a partial perspective view of another embodiment of a cutting tool of the present invention,

19 is a partial perspective view of another embodiment of a cutting tool of the present invention;

20 is a graph showing rotational speed versus centrifugal force.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows an embodiment of a cutting tool 10 of the present invention. Although the cutting tool 10 is generally described as suitable for use as a milling cutter, it should be understood that the cutting tool 10 according to the present invention can be applied to other cutting operations such as turning. Moreover, the cutting tool 10 is designed to be used for high speed milling applications. In terms of materials, high speed milling preferably ranges between about 5,000 to 12,000 m / min or 15,000 to 36,000 surface speed per minute (SFM). In terms of spindle rotation, high speed milling is 10,000 to 40,000 rpm, and in the future up to 60,000 rpm. However, it should be understood that the cutting tool 10 according to the invention is also used for low speed applications. For applications with a cutter speed of about 20,000sfm, Table 1 below provides a description of the relationship between cutter diameter and spindle rotation, where SFM = (π * D * RPM) / 12.

Table 1

Diameter (inches) Spindle rotation, RPM 2.5 30,558 3 25,465 3.5 21,827 4 19,099 12 6,366

1 and 2, the cutting tool 10 shown is in the form of a milling head that is part of a tool for chip removal machining. A plurality of cutting inserts 12 is assembled to the milling head. Each cutting insert 12 is received in a corresponding pocket 14 of the tool holder body 16. In the embodiment fourteen cutting inserts 12 are shown. However, it should be understood that the cutting insert 12 may be more or less depending on design preferences and applications.

The cutting insert 12 is made of a suitable hard material and is preferably harder than the material of the tool holder body 16. In the context of the present invention, the cutting insert 12 is made of many other hard materials, such as conventional cemented carbide, ceramics, cermets, etc., and is a polycrystalline diamond or cubic boron nitride exposed to the cutting edge. a cutting tip in the form of small bodies of (cubical boron nitride).

Preferably, high strength steel is used as the material for the tool holder body 16 which is strong and resistant to chip corrosion.

1 to 3, a tightening wedge 18 is used to hold the cutting insert 12 in the insert pocket 14. Preferably, the tightening screw 20 is used to drive the tightening wedge 18 in the pocket to tighten the tightening wedge 18 against the cutting insert 12 on one side and the body 16 on the other side. Preferably, the tightening screw 20 is a differential screw that functions to tighten and loosen the cutting insert 12 according to 1½ rotation of the tightening screw 20. Most preferably, the tightening screw is loosened by an L-wrench, but may be removed by other known techniques. However, it should be understood that the tightening wedges 18 are also fastened by other known methods and are not limited to differential screws. Moreover, it should be understood that the tightening screw 20 can be designed to loosen the cutting insert 12 having more than or less than 1½ revolutions.

Since the cutting insert 12 requires considerable wear and frequent replacement, the tightening wedge 18 is provided for quick insert change by simple loosening of the tightening wedge 18. Moreover, the tightening wedges 18 provide protection for the tool holder body 16 in the event of a collision with machined parts or equipment that can be easily replaced. Preferably, the tightening wedges 18 are made of high strength material, but also of other strong materials.

4 and 5, the cutting insert 12 can be adjusted by the adjusting screw 22. The adjusting screw 22 is preferably located far from the cutting zone 24. As shown in FIGS. 4 and 5, the adjustment screw 22 is positioned through a recess 25 located on the back 27 of the cutting tool, and the pocket 14 is in contact with the cutting insert 12. Stretches. Due to the position of the adjustment screw 22, it is not exposed to wear from the removed chip or to be damaged in the event of a crash. Moreover, the adjusting screw 22 is vibration resistant with high precision adjustment. Moreover, the adjustment screw 22 must be damaged during service, and the adjustment screw 22 is easy to replace.

In an embodiment, the adjustment screw 22 includes a ball surface 26 at its end in contact with the thrust surface 28 of the cutting insert 12. The adjustment screw 22 also includes a threaded male thread portion 30 that engages with a threaded female thread portion 32 formed in the tool holder body 16, as shown in FIG. 4. Preferably, the threaded male portion 30 and the ball surface 26 of the adjustment screw 22 comprise elastic contact deformation. The adjusting screw 22 is advantageously positioned so that there is no toppling moment during adjustment, and therefore the balance state does not change.

As mentioned above, the adjustment screw 22 allows for axial adjustment of the cutting insert 12. Preferably, as shown in FIG. 5, the adjustment screw 22 comprises a plurality of recesses 34 along the periphery of the head 36 of the adjustment screw 22. When the adjusting screw 22 is fastened to the recess 25 and makes contact with the cutting insert 12, the cutting insert 12 can be adjusted in the axial direction by turning the adjusting screw 22. In particular, the recess 34 is preferably provided such that the adjusting screw 22 can be adjusted by the L-wrench. As shown in FIG. 5, the L-wrench may approach and engage the recess 34 from the side recess 35 disposed on the cutting tool. As noted above, in this method one single device can be used to adjust the adjustment screw 22 and also to drive and tighten the tightening wedge 18. This provides a unified solution for maintaining the wrench. Moreover, no torque wrench is needed. However, it should be understood that other devices may also be used to adjust the adjustment screw 22.

4-7, the tightening wedge 18 is described in greater detail below. In particular, as shown in FIG. 4, the tightening wedge 18 includes an upper engagement surface 38 for engaging the lower surface of the cutting insert 12. Preferably, the upper engagement surface 38 is flat, so as to be adjacent to the substantially flat lower surface of the cutting insert 12. However, it should be understood that the upper engagement surface 38 has other contours, although similar to the upper contour of the cutting insert 12, as long as it can be engaged and tightened with respect to the cutting insert 12. It should be noted that the solid torque from the tightening wedges adds a very small advantage to the resistance to centrifugal loads. Thus, the tightening wedges do not need to be relied on for retention.

The tightening wedge 18 also includes a bottom surface 40. As shown in FIG. 6, in the embodiment the lower surface 40 comprises two planar portions 42 and two elongated grooves 44 spaced therefrom. A round cylindrical portion 46 is disposed between the two elongated grooves 44. The lower surface 40 is received in pairs with the mounting surface 48 (see FIG. 5) disposed in the pocket 14 of the tool holder body 16. In this way, the mounting surface 48 is configured and formed to engage and support the lower surface 40. Accordingly, as shown in FIG. 5, the mounting surface 48 is correspondingly configured to receive and support the lower surface 40 of the tightening wedge 18. It should be understood that the bottom surface 40 may take other shapes and is not limited to the specific configurations described herein.

As shown in FIG. 6, the tightening wedge 18 includes two sides 50 and a threaded male thread portion 52 for receiving the tightening screw 20. Preferably, the flat portion 42 is tapered so that the tightening screw 20 functions to engage and tighten the cutting insert as the tightening screw 20 rotates. In particular, as the tightening screw 20 is pivoted, the tightening wedge 18 moves toward the interior of the pocket 14 and the upper engagement surface 38 is pressed against the lower surface of the cutting insert 12, thus tightening Tighten. It should be noted that the tightening screws are tightened on the same axis as the rotation axis of the tool. Therefore, due to the tightening occurring in the same axis of the tool, the stress caused by the firm torque does not cause deformation of the tool. For example, when assembling an insert to a cutting tool, the user tends to over-torque or under-torque the insert, which causes deformation of the cutting tool. According to the cutting tool of the invention, the shape of the milling cutter is basically unaffected even if the screw is turned excessively or weakly.

Hereinafter, the cutting insert 12 according to the embodiment will be described in more detail with reference to FIGS. 8 to 13. The cutting insert 12 shown comprises an upper cutting surface 60 and a lower supporting surface 62. As noted above, the lower support surface 62 meshes with the upper engagement surface 38 of the tightening wedge 18 and is correspondingly shaped to mate therewith. Although the lower support surface 62 is shown as a plane, it should be understood that the lower support surface 62 may have a different configuration or appearance and may be concave.

Referring to FIG. 5, the upper cutting surface 60 includes an engagement portion 64 for mating with each engagement portion 66 located in the insert pocket 14 of the tool holder body 16. In particular, the engagement portions 64 and 66 are characterized in that shear resistance generated between the engagement portion 64 of the cutting insert 12 and the engagement portion 66 of the insert pocket 14 occurs during the operation of the cutting tool during the operation of the tool. It should be designed to be larger than the shear force. For example, this relationship is shown in FIG. 6 according to another embodiment of the present invention, where F1 is centrifugal force and F2 is shear resistance.

According to an embodiment of the invention, the engagement portion 64 is shown as a number of substantially parallel serrations 67, as shown with reference to FIGS. 8-13. In particular, the serration 67 is spaced evenly or spaced evenly. Unevenly spaced serrations 67 provide error proof positioning of the cutting insert, making the cutting insert made for a particular application unusable for other applications in which it is not considered. As shown in the embodiment, five serrations are arranged. As shown with reference to FIGS. 3 and 5, the serration 67 contacts the mating serration 68 of the insert pocket 14. A plurality of serrations 67 are preferably normal to the centrifugal force F1 and provide redundancy between the mating face of the cutting insert 12 and the mating portion disposed in the insert pocket 14. Provide more. It should be noted that the serration 67 is preferably parallel, or within 10 degree variations, to facilitate manufacturing. Moreover, serration 67 further provides for constant positioning of cutting insert 12.

Although the embodiment describes a number of serrations 67 for use as the engagement portion 64, it should be understood that many other forms of construction are possible as long as the shear resistance is greater than the centrifugal load. Furthermore, depending on the application and design preferences, there may be five or more serrations, or as few as one serration. Moreover, the engagement portion 64 need not be formed parallel to the cutting edge, but can be formed at an angle. Similarly, additional serrations running perpendicular to the serration 67 are also possible, so that the cutting insert can be detached at four different positions instead of two.

Each cutting insert 12 shown in FIGS. 8-12 includes at least one cutting edge or edge. With particular reference to FIG. 8A, the cutting insert 12 shown includes a first cutting edge 70 and a second cutting edge 72. When the cutting insert 12 is mounted to the tool holder body, one cutting edge is exposed and the other cutting edge is substantially encapsulated in the insert pocket 14. For example, as shown in FIG. 3, the first cutting edge 70 is exposed for actual cutting, while the second cutting edge 72 is removed from the cutting zone 24. As such, the second cutting edge 72 is protected from wear by ongoing chips.

As shown in FIG. 8A, the cutting insert 12 includes a cutting tip 74 disposed along the entire cutting edge 70. Preferably, the cutting tip 74 is made of cubic boron nitride or polycrystalline diamond, but may be made of other hard materials. When the cutting insert 12 of FIG. 8 is inserted into the pocket 14, the thrust surface 28 engages the distal end 26 of the adjustment screw 22, as shown in FIG. 4. When the cutting edge 70 is exposed for cutting, the thrust surface 28 is on the backside 80 of the cutting insert 12, as shown in FIG. 8A. When the cutting edge 72 is exposed for cutting, the thrust surface is on the front portion 82 of the cutting insert 12, as shown in FIG. 8A.

Likewise, as shown in FIG. 9A, the cutting insert 12 shown includes a first cutting edge 70 and a second cutting edge 72. When the cutting insert 12 is mounted to the tool holder body, one cutting edge is exposed and the other cutting edge is substantially encapsulated in the insert pocket 14 (see FIGS. 3 and 5). For example, as shown in FIG. 9A, the cutting insert 12 includes a cutting tip 86 disposed at the edge of the cutting insert 12. Preferably, the cutting tip 86 is made of cubic boron nitride or polycrystalline diamond, but may be made of other hard materials. Although not shown, an additional cutting tip is positioned at the opposite edge 88 of the cutting insert 12 so that when the first cutting edge 70 is worn, the second cutting edge of the cutting insert 12 ( 72 may be used.

Likewise, as shown in FIG. 10A, the cutting insert 12 shown includes a first cutting edge 70 and a second cutting edge 72. The cutting insert 12 shown in FIG. 10A is substantially the same as the cutting insert shown in FIG. 8A, except that no cutting tip is provided on either of the first and second cutting edges 70, 72. .

Referring to FIG. 11A, the cutting insert 12 shown includes a first cutting edge 70 and a second cutting edge 72. The cutting insert 12 shown in FIG. 11A is substantially the same as the cutting insert shown in FIG. 10A except that a pair of chip breakers 90 are provided. Lip 90 provides more redundancy and shear resistance to centrifugal loads.

Referring to FIG. 12A, the cutting insert 12 shown includes a first cutting edge 92 and a second cutting edge 94 perpendicular to the first cutting edge 92. When the cutting insert 12 according to FIG. 12A is positioned in the tool holder body, both cutting edges 92 and 94 can be exposed for cutting. Furthermore, both cutting edges 92 and 94 may be provided with cutting tips made of a material different from the cutting insert 12 as described above. Furthermore, it should be understood that other areas of the cutting insert 12 according to FIG. 12A may be provided with cutting tips made of stronger material.

Although FIGS. 8-12 describe various embodiments including five serrations, it should be understood that other configurations are possible. In particular, other forms of engagement may be provided as long as the shear resistance is greater than the centrifugal load. Moreover, the present invention is applicable to certain insert shapes, such as triangles, lozenges, squares, spheres, rounds, hexagons, octagonal inserts, and inserts for the operation of forming grooves.

For example, as shown in FIG. 4, in operation, the cutting insert 12 is positioned in the insert pocket 14 until the drum surface 28 is adjacent to the adjustment screw 22. At this point, the tightening wedges 18 are loosened to an extent to allow the cutting insert 12 to be preferably positioned easily. Preferably, the tightening wedges 18 remain engaged in the insert pocket of the cutting tool during assembly of the cutting insert 12. As noted above, the tightening wedge 18 is driven by the rotation of the tightening screw 20, which drives the tightening wedge 18 relative to the cutting insert 12 and with respect to the plane of the serration 67. Tighten the cutting insert 12 in the normal direction. At the same time, as shown in FIG. 4, the frictional force generated between the tightening wedge 18 and the cutting insert 12 is a serration plane to ensure contact of the thrust surface 28 with the adjusting screw 22. The cutting insert 12 is moved in a direction parallel to. Moreover, the clamping provides a compressive force or preload that compensates for the shear force provided by the serration 67.

As noted above, in accordance with an embodiment, a 1½ turn of the L-wrench is sufficient to mount and eject the cutting insert 12 for easy assembly. Preferably, the tightening wedge 18 remains in the insert pocket 14 during the exchange or replacement of the cutting insert. This reduces the risk of loss because the tightening wedge 18 does not have to be removed from the tool. When the cutting insert 12 is mounted in the insert pocket 14, the cutting insert 12 is adjusted in the axial direction by the adjusting screw 22. As noted above, the L-wrench may be used to engage the recess 34 disposed on the head 36 of the adjustment screw 22 to provide fine adjustment when the cutting insert 12 is mounted.

Once the cutting tool is fully assembled, an important part of the cutting insert 12 is enclosed or encapsulated in the insert pocket 14. According to an embodiment, for example, as shown in FIG. 3, at least 75% of the cutting insert 12 is encapsulated in and rigid within the insert pocket 14 formed by the tool holder body 16 and the tightening wedge 18. Mounted. The cutting insert 12 is encapsulated and due to the extra fastening shape, a small part of the insert breaks off and most of the insert remains in the closed pocket. Thus, unlike the situation in which the entire insert is released as in the prior art, the kinetic energy released by this failure is minimized.

The cutting tool of the present invention is particularly useful for high speed applications because the tool can absorb high centrifugal forces. For example, the cutting tool according to an embodiment of the present invention may be performed in a speed range up to 20,000 SFM, which is an optimal cutting speed for applications using cube boron nitride or polycrystalline diamond. However, as mentioned above, the cutting tool of the present invention can also be used in low speed applications.

With reference to FIGS. 13 and 14, the cutting insert 12 of the embodiment of the present invention is compared with the cutting insert 100 according to another embodiment, where FIGS. 13a and 13b illustrate the cutting insert 12 described above. 14A and 14B illustrate a cutting insert 100 according to another embodiment. As noted above, the cutting insert 12 includes an upper cutting surface 60 comprising five serrations 67 disposed thereon. Like the cutting insert 12, the cutting insert 100 comprises an upper cutting surface 102 and a lower supporting surface 104, where the lower supporting surface 104 has an upper engagement surface 38 of the tightening wedge 18. ) And correspondingly shaped to mate with it. Although the lower support surface 104 is planar as shown, it should be understood that the lower support surface 104 can have a different configuration or appearance, and can be concave. For example, although convex and / or concave surfaces are possible, these types of surfaces are undesirable.

Like the cutting insert 12, the upper cutting surface 102 of the cutting insert 100 is located in the insert pocket 14 of the tool holder body 16, as shown with reference to FIGS. 16 and 17. And engaging portions 108 for mating with each engaging portion 110. In particular, the engaging portions 108 and 110 are characterized in that shear resistance generated between the engaging portion 108 of the cutting insert 100 and the engaging portion 110 of the insert pocket 114 during the operation of the tool is such that the shear force generated during the operation of the cutting tool. It must be designed to be larger. This relationship is shown in Figure 6, where F1 is centrifugal force and F2 is shear resistant. When the cutting tool rotates in the direction of arrow A, engagement portions 108 and 100 are designed such that F2 is larger than F1.

According to another embodiment of the present invention, the engagement portion 108 is shown as a plurality of substantially parallel serrations 120, as shown with reference to FIGS. 14A and 14B. As shown in another embodiment, three serrations 120 are disposed thereon. The serration 120 is in contact with the mating serration 122 of the insert pocket 114, as shown with reference to FIG. 17. Multiple serrations 120 are preferably normal to the centrifugal force F1 and provide further redundancy between the mating face of the cutting insert 100 and the mating face disposed in the insert pocket 114. Moreover, serration 120 further provides constant positioning of cutting insert 100.

Although other embodiments describe multiple serrations 120 for use as engagement portion 108, it should be understood that many other forms of construction are possible as long as the shear resistance is greater than the centrifugal load. Furthermore, depending on the application and design preferences, there may be three or more serrations, or as few as one serration. Similarly, additional serrations extending perpendicular to the serration 120 are also possible, such that the cutting insert can be detached at four different positions instead of two.

Referring to FIGS. 14A, 14B, 16 and 17, the cutting insert 100 also includes a pair of protective lips 124 disposed on the upper cutting surface 102. Preferably, the protective lip 124 is located on the side of the serration 120 and runs substantially parallel thereto. The protective lip 124 protects the tool body 16 from chip corrosion. In particular, the chip is bent down by a protective lip to protect the tool body 16 from corrosion. Preferably, the protective lip 124 is made of any hard material, such as conventional cemented carbide, ceramic, cermet, etc., and includes a portion made of cube boron nitride and polycrystalline diamond. For example, the cutting insert 100 shown in FIG. 14 includes a cutting tip 126 made of cube boron nitride and polycrystalline diamond. However, it should be understood that the cutting tip may be included in other locations as described above, or may not be provided at all.

13B and 14B, the cutting insert 12 and the cutting insert 100 are further compared. In particular, the cutting insert 100 is designed such that h ₂ of the insert 100 is larger than h ₁ of the insert 12. Preferably, the height h ₁ of the insert 12 is about 3.5 mm, while the height h ₂ of the insert 100 is about 4.0 mm. The increased height of the cutting insert 100 increases the strength, but also increases the insert weight and decreases the cutter density. For example, 14 inserts may be used in an embodiment of a cutting tool using cutting insert 12, while 12 inserts may be used in another embodiment of a cutting tool using cutting insert 100. However, as noted above, more or fewer cutting inserts are provided in the cutting tool depending on the application and preference. Moreover, it is to be understood that the height of the cutting insert 12 and the cutting insert 100 may vary depending on the application and preferences and is not limited to the specific values described above.

15A and 15B, the cutting insert 100 includes a first cutting edge 128 and a second cutting edge 130. As shown in FIG. 15A, the first cutting edge 128 is substantially parallel to the serration 120. Referring to FIG. 15B, the first cutting edge 128 is disposed at an approximate angle with respect to the serration 120. In particular, the first cutting edge 128 is arranged at an angle of 0.5 degrees according to a standard deviation of 0.3 degrees. However, it should be understood that the range of angles is possible and is not limited to that shown in FIGS. 15A and 15B.

18 and 19, the cutting insert 100 is mounted to the tool body 116. The cutting insert 100 is mounted to the tool body 116 by the tightening wedge 18 in a manner similar to the above with respect to the embodiment of the cutting insert 12. In particular, the cutting insert 100 is positioned in the insert pocket 114, and the tightening wedge 18 is driven and tightened to the cutting insert 100 by the fastening screw 20. However, the tool body 116 is of another type, which corresponds to the upper cutting surface 102 of the cutting insert 100. In particular, as shown in FIG. 19, the tool body 116 is shaped such that one of the protective lips 124 adjacent to the cutting edge 128 is not encapsulated in the insert pocket 114. In this way, it can be seen how the protective lip 124 bends the chip during cutting.

As mentioned above, the cutting tool of the present invention provides a unique and reliable clamping system that avoids many of the drawbacks of the prior art. For example, since the actual part of the insert is located in the insert pocket of the tool body holder, unused cutting edges are protected from wear. Moreover, certain fastening mechanisms are located away from the cutting zone, thereby protecting them from premature wear. Instead, the cutting insert that is detached and easily replaced is most heavily loaded, causing less damage to the non- replaceable components of the cutting tool. Most importantly, the engagement between the insert and the tool holder body is provided for greater shear area resistance than the centrifugal load, and the resistance is further supplemented by preload from the clamping device. Engagements shall be provided for redundancy allowing the insert to be retained either of the engagement or serration failure. As such, the cutting tool according to the invention is more reliable and less sensitive to wear and failure.

The presently disclosed embodiment is considered in all respects as illustrative and not restrictive. The scope is set forth by the claims rather than the foregoing description and encompasses equivalents and all modifications that come within the scope.

Claims (22)

A tool body comprising at least one insert pocket; The at least one cutting insert comprises an upper cutting surface and a lower support surface with at least one cutting edge, the upper cutting surface comprising an engagement portion for mating with each engagement portion located in the at least one insert pocket, At least one cutting insert for holding in at least one insert pocket; A tightening wedge for tightening the at least one cutting insert against the at least one insert pocket; Wherein the shear resistance generated between the engagement of the at least one cutting insert and the at least one insert pocket during the operation of the tool is greater than the centrifugal force generated during the operation of the cutting tool. The cutting tool of claim 1, wherein the engagement portion of the upper cutting surface includes a plurality of parallel serrations for mating with each of the plurality of parallel serrations included in the engagement portion of the at least one insert pocket. The cutting tool according to claim 2, wherein there are five serrations on the upper cutting surface of the at least one cutting insert and five serrations on the engagement of the at least one insert pocket. 4. The cutting tool of claim 3, wherein the serration is parallel to at least one cutting edge. 3. The method of claim 2, further comprising first and second protective lips disposed on the upper cutting surface and extending substantially parallel to a plurality of serrations of the at least one cutting insert, wherein the protective lips extend over the upper cutting surface. A cutting tool characterized by the above-mentioned. 6. The cutting tool according to claim 5, wherein there are three serrations on the upper cutting surface disposed between the first and second protective lips. The cutting tool of claim 1, wherein about 75% of the at least one cutting insert is encapsulated in at least one insert pocket. The cutting tool of claim 1, further comprising a tightening screw for driving the tightening wedge in the at least one insert pocket and for tightening the tightening wedge against the at least one cutting insert. 9. The cutting tool of claim 8, wherein the tightening screw is a differential screw. 10. The cutting tool according to claim 9, wherein the at least one cutting insert is released by 1½ turn of the differential screw. The cutting tool of claim 1, further comprising an adjustment screw for adjusting at least one cutting insert. 12. The cutting tool according to claim 11, wherein the adjusting screw is located at a position far from the cutting zone. 12. The cutting tool of claim 11, wherein the adjustment screw comprises a ball surface in contact with the thrust face of the at least one cutting insert, and wherein the ball surface and the thrust face of the adjustment screw comprise elastic contact deformation. . The cutting tool according to claim 1, wherein the cutting tool is a high speed milling cutter. An upper cutting surface and a lower supporting surface having at least one cutting edge, the upper cutting surface including an engaging portion for mating with each engaging portion of the cutting tool, the engaging portion being generated during operation of the cutting tool. Cutting inserts characterized by providing greater shear resistance than centrifugal forces. 16. The cutting insert according to claim 15, wherein the engaging portion of the upper cutting surface comprises a plurality of parallel serrations for mating with each of the plurality of parallel serrations included in the engaging portion of the at least one insert pocket. 18. The cutting insert according to claim 16, wherein there are five serrations on the upper cutting surface of the at least one cutting insert and five serrations on the engagement of the at least one insert pocket. 18. The cutting insert according to Claim 17, wherein the serration is parallel to at least one cutting edge. 17. The method of claim 16, further comprising first and second protective lips disposed on the upper cutting surface and extending substantially parallel to a plurality of serrations of the at least one cutting insert, wherein the protective lips extend over the upper cutting surface. Characterized by a cutting insert. 20. The cutting insert according to claim 19, wherein there are three serrations on the upper cutting surface disposed between the first and second protective lips. Providing a cutting tool comprising a tool body with at least one insert pocket; Inserting at least one cutting insert into at least one insert pocket; Driving a tightening wedge in the at least one insert pocket and tightening the tightening wedge against the at least one cutting insert such that about 75% of the at least one insert is included in the at least one insert pocket; Adjusting the tightening wedge to engage or remove at least one cutting insert. 22. The method of assembling a cutting tool according to claim 21, wherein the at least one cutting insert is released by 1½ turn of the tightening screw.

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